This invention relates to improved clutch apparatus, and more particularly to an improved slip or safety clutch.
Most devices of the prior art which perform a similar function to this invention are relatively expensive and require several fabricated parts. Some of these are known as spring loaded clutches or spring loaded clutch couplings. These rely on the pressure of a spring device to maintain force and thus friction between two rotating surfaces. When the value of the design torque is exceeded in operation, the device slips in rotation to protect a mechanism from damage.
The prior art devices, in addition to being complex and expensive for the function performed, rely on the friction between two surfaces to provide slip resistance. The slip resistance value will vary from part to part and from time to time depending on a number of design variables. Further, it is more difficult and expensive to provide for corrosion resistance in these devices when compared to the clutch apparatus of the invention.
Devices are also known which utilize radial deformable members made of rubber, rubber composition, or rubber and fabric composition. These members deform and provide a scraping action resulting in excessive wear of the members and a substantial amount of radial movement. The torque and life capability of such rubber or rubber fabric type composite members is limited.
Still other devices use different spring configurations requiring shimming, hardened U-shaped spring strips, or spring rods which may be center flexed, or with ball and detent type arrangements. None of these devices, however, is suitable for providing a two piece clutch with both a unitarily formed inner and outer member.
In order to overcome the foregoing problems and limitations, an improved slip or safety clutch is hereinafter described.